Welcome to the ALR site Joe! You will indeed get lots of advice here, and perhaps some of it may rub your fur backwards at times. If you intend to build a full stocked Hawken flint rifle, you have bitten off a good chunk on which to chew. There are nuances in these rifles that will make or break the build, as I see you are interested in making a good effort to get it 'right'.
It is my opinion that Jim Gordon's "Great Gunmakers for the Early West" Volume III, titled "Western US" is your best reference work on this particular rifle. In it, you'll be able to study several examples of full stocked Hawken rifles, though none have flintlock ignition at this time.
Do you notice that I refer to the rifles as "HAWKEN" RIFLES - NOT HAWKENS. I have seen this mistake many times and it always grates on me. My philosophy is that if you can't get the name right, the chances are slim you'll get the build right.
So study as many examples as you can find from every source, buy the best components that you can find and afford, and enjoy the ride. Ask lots of questions. There are a few of us here who also have a warm spot for Hawken rifles, and we'll help where we are able.
I see Acer Sac-o-rum has beaten me to the punch. Notice he refers to the rifles collectively as "Hawkens", which is correct. But a singular rifle is a "Hawken".